What E:28 Means
The service table shows E:28 as an AquaSensor problem, with the appliance operating without the AquaSensor. The internal check results are that the appliance is without an AquaSensor at all, or that calibration of the AquaSensor was not successful, and one of the listed checks is simply whether the AquaSensor is dirty.
Common Causes of E:28
- A film or deposit clouding the AquaSensor's optical window
- A calibration that did not complete successfully
- A wiring problem between the sensor and the control
🔧 One Safe Check You Can Try
Clean the sump thoroughly, including the small optical window the sensor looks through, since the table's own question is whether the AquaSensor is dirty before anything else is considered.
⚠ Why You Shouldn't Go Further Than That
- The sensor judges soil by light passing through the wash water, so it is degraded by exactly the residue it lives in - and abrasive cleaning of that window ends its usefulness for good.
- Calibration is a service routine rather than a user setting, so a sensor that will not calibrate needs the right procedure rather than repeated attempts.
- Reaching the sensor means working under the tub floor, where lifting the sump risks pinching the gasket that keeps water inside the machine.
Opening a panel to inspect or repair something yourself doesn't automatically cancel your manufacturer's warranty — but it can risk accidental damage, and some manufacturers do have specific service conditions. Check your product's warranty terms, or ask us, before deciding.
Technical Reference
- Code
- E:28
- Appliance
- JennAir dishwasher
- Maker documentation
- JennAir owner manuals and use & care guides
- Checked
- September 2026
Code meanings can change between control generations. Before acting on a code, match the full model number on your appliance's rating label against the manual for that model. We are an independent repair service, not affiliated with Whirlpool Corporation.